The opening of the film informs the audience about the infamous Japanese attack on Pearl Harbor on December 7, 1941 which hurtled an unsuspecting America into World War II. The West Coast of the United States was fearful that the Japanese would attack California next. These were actual fears that were quickly realized by its citizens, and that extreme caution and observation was needed to thwart any attempt which made invasion possible. The film is set just six days after the Pearl Harbor attack.

In the first few opening minutes of the film, Spielberg, and writers Bob Gale, John Milius, and future director Robert Zemeckis (Back to the Future trilogy) fantastically lampoon Spielberg’s Jaws opening by using the very same actress to re-create her skinny dip scene in the early morning hours. Veteran Spielberg composer John Williams even re-creates his famous theme music. The female swimmer is instantly caught on the periscope of a Japanese submarine which is prowling the California coastline for a worthy military target.